Next model of Launcher-Shells. The V7 Snake-Eye

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WaterWolf
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Next model of Launcher-Shells. The V7 Snake-Eye

Post by WaterWolf » Thu Aug 02, 2007 4:13 pm

This the Seventh version of my new line of WB-Shells. Christened the V7 Snake-Eye, for its resemblance to the Mark 81 Snakeye Bomb.
This project is the result of about a year of tinkering with shell designs and I have reached the point where it has gotten so good that its very hard to improve, but I would appreciate any ideas people here have.
The first section, the "Flare" is built out of the bottom of an empty, 1-lb sour-cream container, which has been cut to fit the 3-inch barrel with an impressively air-tight seal.

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Container before cutting.

You can achieve this easily by placing the container bottom down into a 3-inch PVC barrel, then using a pen to mark a circle flush with the PVC pipe. Cut along the line. Now you have an almost perfectly air-tight piece. Some extra trimming may be necessary, but this should get you very close.

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Container after cutting.

The second part, the "Body" is a section of Pringle's can that has been cut in several ways.

First, slice off the rim that holds on the Pringle's can. Wrap it all in JUST ONE LAYER of duck tape, no more. We are NOT trying to get it air tight here, the tape is just to strengthen it. Slide the Pringle's can down a 3-inch pipe, it should fall easily.
Insert the Flare piece, bottom first, into the open end of the Pringle's can, it will go in a little way and then stop. Measure 5 inches from the outer edge of the Flare up the Pringle's can. At the 5 inch point, cut the Pringle's can. Wrap one more layer of duck tape around the Pringle's piece and some of the exposed Flare to hold them together. Try not to put any duck tape on the actual rim of the Flare. Cut some back if necessary.

Cut four vertical slits down the sides of the Pringle's can. Not all the way down, just to the point where the flare is inside the shell. Flex these flaps out once and then back to their regular position.

Insert one balloon. It should not project out further than the front edge of the Pringle's can, if it does, you are using too large a warhead.

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Finished shell without warhead.

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Finished Shell with warhead.

When the round is slid down the barrel, the sides of the nose will be pushed together by the inside of the barrel and the balloon will be held between them. When the launcher is fired, the round flies out at maximum possible speed, due to the air-tight, but low friction Flare. As it hits still air outside the barrel, the cut sections on the Body deploy, releasing the balloon to continue on its flight without slowing. While the fins of the can, catch air like a drag chute and cause the shell to drop to the ground fairly close to the launch-site.

This shell has the highest air-efficiency level I've ever seen, while at the same time staying cheap and easy to use. The more efficient a shell is, the farther it will be able to send a balloon with the same amount of air-power.

The previous champion for air-efficient WB-Shells in my opinion had been DX's design, a Pringles can wrapped in several layers of duck tape. Which I had noticed tended to cause a significant amount of friction inside the barrel. And so, after a lot of work, I've built my own low friction but air-tight design. The Pringle's can DOES make up a portion of the shell, but it is only being used to hold the balloon and prevent rupture or friction.
After performing many tests, I have found that the Snake-Eye has the Pringle's method beat on several accounts:

It has approximately 15% higher efficiency.
About two shells can be made out of a Pringle's can, instead of just one.
Balloons are less likely to detonate inside the barrel when firing.
The Snake-Eye has a lower drop-off distance. (Making retrieval faster.)
They weigh less and do not include any metal parts, such as the Pringle's metal bottom.
(Which could be potentially painful if struck at close-range.)
It is shorter in length, making it easier to transport and takes up less space in the barrel.
(This is also highly relevant for one of my more important "Coming soon" items)

The only problems I've found with the V7 Snake-Eye is that it is so air tight that the pressure behind it builds up and makes it difficult to push down the barrel. This however can be solved by either cutting a small notch in the flare, or by installing my (***CLASSIFIED***) piece that will soon be unveiled.

The other slight issue (though the Pringle's method has this too) is that the body can become somewhat soggy when it gets wet.
If you are able to however, then you can use a plastic tennis-ball container for the body, instead of a Pringle's-can. Follow the same instructions, but with the different material. The one problem with this is that buying that many cans could be expensive ($3.00 each for me), but if you can find a cheap source of these (such as a friend who plays tennis, or a fitness center with a tennis-court) then I would highly recomend building the Snake-Eyes with the plastic containers, as they are water proof, harder to damage and seem to cause even less friction with the sides of the barrel, making them more efficient to load and fire.

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Last edited by WaterWolf on Sun Aug 05, 2007 5:06 pm, edited 1 time in total.
Reason: New information.
Captain-Canis: Founder of the Maple-Mountain-Marines.
Terrifying, but oddly refreshing.
-B.D.

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Silence
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Post by Silence » Thu Aug 02, 2007 7:33 pm

This design is indeed very well-refined. Nobody else has taken such a close look at sabots, so you're consequently way ahead of the curve. Nice job! :cool:

If there's too much friction, you'll want to lubricate the sabot, make it narrower, or use less duct tape over it. I wouldn't worry too much about the airseal - especially with a longer barrel, you should make use of the volume of air and make sure there's as little friction as possible. The first thing I would do would be to cover up the duct tape on all your sabots with packing tape or something even less sticky.

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WaterWolf
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Post by WaterWolf » Thu Aug 02, 2007 8:12 pm

Actually, I tested all the things you said above and found that the air-seal was of critical importance. Without it, even in a longer barrel, much of the air would simply rush past the shell if it wasn't tight.

When I began working on my new type of WBL a few months ago, it ended up evolving itself into many sub-projects alongside it and these are what you are now seeing. The shell I found was one of the most important items that was in desperate need of improvement for my launcher.
I required a sabot that was extremely efficient, short, cylindrical and with a high drop-off.

I do lubricate the launcher, but I prefer a shell that does not rely on it.
Packing tape also tends to peel and fall off.
Captain-Canis: Founder of the Maple-Mountain-Marines.
Terrifying, but oddly refreshing.
-B.D.

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SSCBen
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Post by SSCBen » Fri Aug 03, 2007 2:01 am

This is a pretty great innovation. I don't think any other sort of sabot should be made after looking at this.

One suggestion though if you don't want to use a messy lubricant such as petroleum jelly or silicone spray, both of which can make your hands greasy, is to try a Teflon tape with an adhesive on one side. I considered them before for something and this tape is available on McMaster-Carr. I bet you could make an even more efficient sabot with Teflon. wink.gif

Though that might be your classified idea...

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DX
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Post by DX » Fri Aug 03, 2007 2:30 am

As posted at WWc, see if a tennis ball can may eliminate the soggyness that a pringles can experiences. Other than that, also as posted at WWc, I love the design! :cool:
Mess With the Best, Get Soaked Like the Rest!

2004 Red Sox - World Series Champions
2007 Red Sox - World Series Champions!

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WaterWolf
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Post by WaterWolf » Sun Aug 05, 2007 5:07 pm

I have just edited the above article to include tennis-ball cans, which I have found are able to fit my needs perfectly. I've left the instructions for Pringle's-cans up, because some people might prefer to use them instead since they are a cheaper solution.
Captain-Canis: Founder of the Maple-Mountain-Marines.
Terrifying, but oddly refreshing.
-B.D.

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